Biotransformation Of Huperzine A By Endophytic Fungi Isolated From Huperzia Serrata

Microbial transformation has been proved to be an effective method in the structural modification of natural products.The development of new microbial resources is of vital importance to increase the diversities of the transformation reaction types and the structural diversities of the transformed products.With the aim of enriching the structural diversities of the host plants,the present study tried to explore in the endophytic fungi for the microorganisms with the ability to transform the constituents of their host plant.A total of 56 strains of endophytic fungi were isolated from the medicinal plants Huperzia serrata.In the preliminary screening,two strains of them(Guignardia sp.ZJUT-HS03 and Bjerkandera sp.ZJUT-HS19)were found to possess the ability of transforming huperzine A(hup A),a representative alkaloids of the host plant H.serrata.In the subsequent study,eight compounds were identified from the transformation system of Guignardia sp.ZJUT-HS03 and Bjerkandera sp.ZJUT-HS19,with six 1-6 from the former and two from the latter.Of all the isolates,compound 7 was a transformed product of hupA,which had been reported twice by biotransformation of hupA by two microorganisms including an endophytic fungus of H.serrata.The results revealed to some degree the characteristics of the microbial transformation of natural products,in particular,the transformation of the host plant constituents by endophytic fungi.It indicated that harvesting plant endophyte for biotransformation of the host originated constituents may represent a new method for the structural modification of natural products.